1. Field of the Invention
The present invention relates to a pressure detector for detecting a pressure in a space such as a combustion chamber of an internal combustion engine.
2. Description of Related Art
An example of a pressure detector of this kind is disclosed in JP-A-7-253374. The pressure detector disclosed therein includes a housing to be installed in a combustion chamber of the engine, a pressure-sensitive element contained in the housing, a pressure-transmitting member for transmitting pressure imposed on the housing to the pressure-sensitive member, and an output connector for taking out electrical signals of the pressure-sensitive element.
In this pressure detector, a connecting member for electrically connecting the pressure-sensitive element to the output connector is used. As this connecting member, a terminal assembly that includes plural terminals held by hermetic members is used. One end of the terminals in the connecting member is connected to a connector pin of the output connector by welding, and the other end is connected to the pressure-sensitive element by wire bonding.
When this type of the pressure detector is used as a combustion pressure sensor, a portion of the housing on which the combustion pressure is imposed is inserted into a hole formed in the engine block. In order to save a space for installing the pressure detector to the engine, it is required to minimize a diameter of the housing. In the conventional pressure detector, however, the diameter of the housing is determined by the size of the terminal assembly, because the terminal assembly is the largest component among components to be contained in the housing.
Further, the diameter of the housing has to be set to cover all dimensional fluctuations of the terminal assembly. It is difficult to reduce the dimensional fluctuations in the terminal assembly because the dimensional fluctuations are composed of plural fluctuations such as those in the size of the terminal itself, a space between terminals and the size of the hermetic members. Therefore, the diameter of the housing is set to such a size that allows the largest dimensional fluctuations in the terminal assembly. Therefore, it has been difficult to reduce the diameter of the housing.